Tomarry

Tom Riddle and Harry Potter have been together for hundreds of lives getting reincarnated again and again with each other. Tom blamed it on Harry for becoming the Master of Death. Harry blamed it on Tom for making him a horcrux, but they settled their differences during their fourth life or so, they kind of had to seeing as Harry reincarnated as Tom's heir, and Tom didn't want to impregnate another woman.
This life though they want to create some chaos.
And Death only ever indulges it's master. So it obviously lets them, it made a mistake....
Not for him though he's never been happier the amount of deaths... oh so happy. Life, and Fate on the other hand, he'll have to avoid them for a few 100 years until they forget about it